In a typical wireless communication system, a session key is distributed among the transmitting and receiving communication devices when a communication session is set up. The session key is then used by the transmitting communication to perform Layer 2 or Layer 3 encryption on data transmitted over-the-air. No physical layer, that is, Layer 1, encryption is performed, that is, there is no encryption of the modulated waveform. In addition, typically only the user data is encrypted and not the pilot symbols and synchronization symbols, which symbols must be used as a reference for timing synchronization and fading recovery.
The performance of Layer 2 or Layer 3 encryption leaves the data vulnerable to decryption by an intercepting communication device that either intercepts the session key or that decrypts the data by application of brute force. Therefore, a need exists for a method and apparatus that makes an air interface more secure against decryption by an undesired interceptor of a communication in a wireless communication system.